Lubricating oil



Patented Apr. 11, 1939 UNITED STATES- wa t-2 1 GFFIC'E I 't m 1 nnnnijca rma 01!.

Clarence nut. minor is Standard Oil 'ompany, Chicago, Ill, a corporation of Indiana No Drawing; November 16, 198i,

Serial No. 111,684

This invention relates to lubricants and, in

particular, to addition agents imparting improved properties to lubricants.

This invention has particular utility in improving the lubricating properties 01' lubricating oils and/or in preventing or inhibiting the corro-. sion of hard metal alloy bearings such as copper-lead, ca-nickel and cadmiumsilver bearings which, to a large extent, have re- I m placed soft metal bearings, such as Babbitt metal,

in the trend toward internal combustion engines having high compression ratios and increased acceleration and increased, speed characteristics.

The use of the "hard metal" bearings has created l5 lubricating and corrosion problems, particularly in connection with highly refined oils, some oi which may be very corrosive to bearings oi the hard metal type. 1 I

As used herein highly refined" lubricating oil means visco'us oils which have a minimum via-- cosity of S. A. E. oils, or higher, and'whlch have been subjected to such refining pr that the parafllniclty of the oil is markedly inlubricating oils cause corrosion to alloy bearings of the hard metal type such as cadmium-silver alloy bearings to the extent of about 5 mg/cm.

and even greater, when such bearings are sub- 3o merged for 25 hours or less in an air agitated oil which has been preoxidized at about 340-F. tor

25 to 50 hours. The motor oils may be highly refined ,lubricatin'goils as such or mixtures 01 highly refined lubricating oils with less highly *reflned lubricating oils, or stated in another way, mixtures of corrosive oils and non-corrosive oils, examples of the latter being lubricating oil fractions from Winkler Crude or crudes of the Winkler I have found that corrosion of alloybearings of the cadmium-silver type can'be inhibited and highly desired properties can be imparted to lubricating oils by adding thereto up to 2%, but preferably 0.05% to 0.75%, of certain organic materials, particularly monovalent radical substituted heterocyclic organic compounds selected from the group consisting oi thiazines having the general formula creased. It has been found that highly refined and thlazoles having the general formula E N-t c=s s or 3-1 s 'c ==o i i i in which B may be substituted alkyl and/or aryl and/or aralkyl and/or amino and/or amino alkyl and/or alkyl substituted amino and/or mercapto and/or alkyl mercapto and/or aryl mercapto radical or radicals.

The term thiazole as used herein includes the thio monazoles, the '(1-2-3, 1-2-4, 1-2-5, and

' 1-3-4) thio diaaolesand the (1-2-3-4 and 1-2-3-5) Mu-phenyl-alpha dimethyl gamma methyl penthiazoline; Mu-mercapto-gamma-methyl penthiazoline Mu-mercapto-gamma-butyl penthlazoline Gamma-methyl-alpha-dimethyl penthiazoline Para thlazine 2,4 dibutyl thiazine Some of the foregoing compounds may not be completely soluble in the lubricant, in which case eil'ective results are obtained by suspending the inhibitor in the lubricant by means of small amounts 01' a peptizing agent such as aluminum naphthenate, aluminum stearate, etc.

When highly refined motor oils are used in internal combustion engines provided. with bearings of the cadmium-silver and copper-lead type the bearings, after a comparatively short time,

i'ail due to the corrosion of the bearing metal.

This is probably due to the removal of certain constituents from the oil which behave ascorroa I have found that when small.-.:

sion inhibitors. amounts, for example up to 2%. but preferably 005% to 0.75%, of the foregoing compoundsare comprises adding to said lubricating oils in a. small but suificient proportion to substantially retard said corrosion a monovalent radical substituted heterocyclic organic compound selected from the group consisting of thiazines having the general formula v iii" iii" Lei LJ" i. it it it and thiazoles having the general formula in which R is a radical selected from the group consisting of, alkyl, aryl, aralkyl, amino, amino alkyl, mercapto, alkyl mercapto and aryl mercapto radicals.

2. The method of preventing corrosion of bear-- ing metal alloys having the corrosive susceptibility of alloys of the group consisting of cadmium-silver alloys, cadmium-nickel alloys andcopp er-lead alloys in the presence of-highly refined lubricating oils normally corrosive to said bearings which comprises adding to said lubricating oils about 0.05% to about 0.75% of a mono- I valent radical substituted heterocyclic organic compound selected from the group consisting of thiazines having the general formula and thiazoles having the general formula in which R is a radical selected from the group consisting of alkyl, aryl, aralkyl, amino, amino alkyl, mercapto, alkyl mercapto and aryl mercapto radicals.

3. The method of preventing corrosion of bearing metal alloys having the corrosive susceptibility of alloys of the group consisting of cadmium-silver alloys, cadmium-nickel alloys and copper-lead alloys in the presence of highly refined lubricating oils normally corrosive to said bearings which comprises adding to said lubricating oils an alkyl thiazole in a small but suflicient proportion to substantially retard said corrosion.

4. The method of preventing corrosion of bearing metal alloys having the corrosivefsusceptlbility 01 alloys of the group consi ti g 91 m, mium-silver alloys, cadmium-nickelfalloys" and copper-lead alloys in the presence of highly refined lubricating oils normally corrosivejtofsaid bearings which comprises adding to said lubricating 01] from about 0.05% to-about' 0;75%*of a tributyl thiazole.

5. The method of preventing corrosion or bear- Y ing metal alloys having the corrosive susceptibility 01' alloys of the group consisting of 'cadmium-silver alloys, cadmium-nickel alloys and.

copper-lead alloys in the presence of highly refined lubricating oils normally corrosive tojsaid bearings which comprises adding to said lubricating oils an aryl thiazole in a small but suflicient proportion to substantially'retard said corrosion.

6. The method of preventing corrosion ot'bearing metal alloys having the corrosive susceptibility of alloys of the group consisting of cadmium-silver alloys, cadmium-nickel alloys and copper-lead alloys in the'presence of highly refined lubricating oils normally corrosive to said bearings which comprises adding tosaid lubricating oil from about 0.05% to about 0.75% of a triphenyl thiazole.

'I.- The method of preventing corrosion of hearing metal alloys having the corrosive susceptibility of alloys of the group consisting of cadmium-silver alloys, cadmium-nickel alloys and copper-lead alloys in the presence of highly refined lubricating oils normally corrosive to said bearings which comprises adding to said lubrieating oil from about 0.05% to about 0.75% of a mercapto thiazole.

CLARENCE M. 

